1. Field of the Invention
This invention relates to an optical imaging apparatus which radiates a low coherence light beam onto a test object, receives optical information from light scattered by the object, and constructs therefrom a cross-sectional image of the object.
2. Description of the Related Art
Recently, for diagnosis of a sick biological tissue, optical CT apparatuses have been developed which provide optical information regarding the internal structure of that tissue, in addition to imaging apparatuses which provide optical information regarding the surface condition of that tissue.
The optical CT apparatus provides cross-sectional images of a living body by delivering pulses with a duration of some pico-seconds, thereby obtaining the information of its internal structure, but a laser light source which is required for delivering such ultra-short pulses with a duration of pico-second order is expensive, large in size and cumbersome for handling.
Recently, interference type OCT (optical coherence tomography) apparatuses which provide sectional images of a test object using a low coherence light beam is disclosed, for example, in Japanese Unexamined Patent Publication No. 6-511312.
In this particular previous example, however, no attention has been paid to the variation in length of individual optical probes which is often encountered when an old probe is replaced with a new one. Such variation in length may narrow the range within which acquisition of sectional images is possible, and, in worst cases, may completely annihilate the possibility of obtaining sectional images.
Further, it is desirable for the probe, when it is used in a body cavity, to operate in conjunction with an endoscope. In such case, it would be convenient if the probe could be inserted through a forceps channel of that endoscope. But, no previous apparatuses have been so designed as to allow their adjunct probes to be exchanged as appropriate according to the length of forceps channel of an endoscope to be used in cooperation.